Illumination panel

ABSTRACT

An illumination panel includes a transparent structural core having two opposing surfaces, a matrix of light releasing dots substantially covering both the opposing surfaces, and a protective panel in abutting contact with each of the opposing surfaces whereby the dots are an adhesive for bonding the core to the protective panels and wherein the density or size of the dots increases across the illumination panel in a direction away from an illumination panel edge adjacent a light emitting element.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/258,034, filed Sep. 21, 2011, which is a U.S. National StageApplication of International Application No. PCT/AU2010/000339, filedMar. 24, 2010, which claims priority from AU 2009901272, filed Mar. 25,2009, said patent applications hereby fully incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates to an illumination panel and, in particular, apanel for use in building and display applications including illuminatedsignage.

BACKGROUND OF THE INVENTION

Illuminated signage, advertising and display boards are in popular useacross the world. These signs usually incorporate discrete lightingwhich has the effect of illuminating the whole of the sign. There havebeen a number of past suggestions for using translucent plastics withedge lighting whereby the light is released by a matrix of dots to fullyand evenly illuminate the entire surface area of the sign. Well knownarrangements of this type of sign utilise an acrylic panel that hasprinted thereon a graded matrix of ink dots on one or both faces of thepanel.

The dots of ink affect the refractive and reflective nature of theacrylic and allow light introduced along an edge of the panel to bereleased across the whole surface area of the panel. When the dots arecarried on both sides, the light reflects and refracts more effectivelythrough both surfaces. In one option, a reflective film or sheet isplaced on one side causing the light released on that side to bereflected back through the panel so the majority of light leaves thepanel only through one (“front”) surface.

The same process of controlled, even light release can be achieved bylaser etching the surface of an acrylic panel.

A problem with lighting systems of the kind described above is that theacrylic panel which carries the matrix of printed dots or laser etchinghas to be handled very carefully. If the panel becomes scratched orsubjected to moisture, light escapes as bright spots thereby upsettingthe even light distribution across the surface of the panel. Thevulnerability of the surfaces of the acrylic panel reduces the effectiveuse of such panels.

Furthermore, these panels cannot by themselves, operate as structuralelements. In order to be used as structural elements they mustincorporate a supporting skeleton such as an edge frame.

Other, small non-structural illumination panels are also used asilluminating screens for liquid crystal displays in devices such ascalculators and mobile phones. The planar elements of these panels aretypically held together by the calculator or phone casing, or some othermechanical means such as screws.

It is consideration of the problems associated with these structuresthat has brought about the present invention.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided anillumination panel comprising a transparent structural core having twoopposing surfaces, a matrix of light releasing and distributing dotssubstantially covering both said opposing surfaces, and a protectivepanel in abutting contact with each of said opposing surfaces wherebythe dots are an adhesive for bonding the core to each of the protectivepanels and wherein the density or size of the dots increases across theillumination panel in a direction away from an illumination panel edgeadjacent a light emitting element.

The transparent structural core, protective panel and adhesive dotstherebetween thus form an integral structure.

Where used herein, the term “light releasing dots” is intended toinclude the effect of light reflecting and refracting from dots on thesurface of a transparent structural core. As such, the surface of thepanel is fully and evenly illuminated.

The matrix of dots may be applied to the transparent core by etching,painting, screen printing, printing or spraying or any one of a numberof application techniques such as transfer from a film or even as partof a film or panel that then becomes the protective panel.

Alternatively, the matrix of dots may be provided by localized spotapplications of energy, such as laser energy from a laser, or highfrequency ultrasonic acoustic vibration from a sonotrode.

In a preferred embodiment the array of dots may be provided by laseretching the surface of the panel to define the array of dots while alsobonding the protective layer to the core.

Preferably, the core is acrylic and the protective panel may be anysuitable material that will bond to the core via the medium of the dots.The protective panels protect the core surface so the light distributionestablished by the matrix of dots remains fixed and the core isprotected from further contact.

In one embodiment the protective panels bonded to the core are bothdiffuser panels. In another embodiment, a reflective protective panel isattached to one side of the core with a diffuser panel attached to theother. Preferably, when the protective panel is a diffuser panel itcomprises glass, acrylic, polycarbonate or various translucent plasticmaterials. The protective panel may be extremely thin, in the form of afilm. Preferably when the protective panel is a reflector panel itcomprises a plastic material such as acrylic, high impact polystyrene,or glass, metal such as aluminium composite or a laminate such as theacrylic and polyester surfacing provided under the Laminex® trade mark.

In accordance with a still further aspect of the present invention thereis provided a method of producing an illumination panel of the presentinvention, the method comprising the steps of placing a protective panelin abutting parallel contact with a transparent core and establishing amatrix of light releasing dots by applying energy through the protectivepanel onto the surface of the core to adhere the protective panel to thecore and provide light distribution across the transparent structuralcore.

The activating energy may be, for example, laser energy, heat (thermal,IR etc) or ultrasonic energy.

The dots described above can be of any size or shape and are, forexample, square, round, linear, rectangular, triangular, doughnut, orany other shape, even an irregular shape. The dots may be clear,translucent or opaque and, more preferably, light coloured, for example,white. The light releasing dots may increase along the panel in density,size or combinations thereof across the panel in a direction away from alight source applied to one or more edges of the panel.

The illumination panel of the present invention is suitable for a widerange of applications where a structural illumination panel is required.Applications for which the illumination panel of the present inventionmay be included as a structural element include: shelves for bookcasesor display frames, panels for cabinets such as cupboards, open displaysor refrigerators, signs including road signs and advertising signs, andsplashbacks such as those used in kitchens and bathrooms.

The illumination panel of the present invention is particularly welladapted for use with light sources such as light emitting diodes (LEDs)which can be located adjacent an edge or one or more edges of the panel.The light source may be powered by any convenient power source, such asmains electricity, battery or solar power.

In another aspect of the present invention there is provided anilluminated solar powered panel comprising a transparent structural corehaving two opposing surfaces, a first matrix of light releasing dots anda second matrix of light releasing dots substantially covering both saidopposing surfaces and a protective panel of reflective material inabutting contact with the uppermost of the opposing surfaces, wherebythe first matrix of light releasing dots are an adhesive for bonding thecore to the protective panel and wherein the density or size of the dotsin the first matrix increases across the panel in a direction away froma panel edge said protective panel carrying a plurality of solar cellswhereby the solar cells generate electricity that is passed to a batterypack or accumulator and power from the battery pack or accumulator isfed back to a light source positioned along at least one edge of thepanel to allow light to be introduced and distributed by the firstmatrix of dots and released through a diffuser bonded to the lowermostsurface of the core by the second matrix of light releasing dots.

Preferably, the protective panel consists of solar film or solar cells.For example the solar film may be the protective panel. Alternativelythe protective panel may comprise solar film or solar cells. Forexample, solar film or solar cells may be bonded to a surface of theprotective panel.

In a preferred embodiment, the protective panel comprises or consists ofsolar cells with the rear surface treated or painted to act as areflector.

In essence, embodiments of the present invention stem from therealisation that, contrary to the teaching of the prior art, it ispossible to remove the frame or case used to hold components of thelight generating panel together, and achieve the protection of the waveguide surfaces by bonding the diffuser and reflector to the wave guideby a matrix of light releasing and reflecting adhesive dots. Thisreleases the edge light panel elements from the need for a frame andallows the panel to be used for a multitude of new applications. Becausethe panel components are bonded together, the panel becomes structuralas well as illuminating, and this is a very practical and highlyinnovative development.

Advantages provided by illumination panels according to the presentinvention include the following: the panels are structural and can beused without frames; during manufacture, the panels can be finishedusing well known techniques such as laser cutting, sawing, edge-banding,pre-milling and corner rounding and edge routing; the panels can bemanufactured in a wide range of sizes and laser cut to any desiredshape; the panel manufacturing process can be straightforward andeconomical.

DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way ofexample only with reference to the accompanying drawings in which:

FIGS. 1a (i)-1 d(ii) comprise cross sectional plan views of illuminationpanels of the prior art (FIGS. 1a, 1b, 1c and 1d ) in both (i) exploded,and (ii) assembled conformations. The prior art illumination panels arethose disclosed and taught in US 2008/0037272 by Song et at (FIGS. 1a(i) and 1 a(ii)), US 2003/0231483 by Higashiyama (FIGS. 1b (i) and 1b(ii)), U.S. Pat. No. 6,918,679 by Wu (FIGS. 1c (i) and 1 c(ii)) and JP100 21720 (FIGS. 1d (i) and 1 d(ii)).

FIGS. 2a and 2b are views of a double sided illumination panel accordingto the present invention in exploded plan view (FIG. 2a ) and in crosssection (FIG. 2b ). In contradistinction to the prior art of FIGS. 1a(i)-1 d(ii), the illumination panel of FIGS. 2a and 2b have a core 11having opposed surfaces 12 and 13, each of which is covered by a matrixof opaque, translucent or clear dots 20 that adhere protective panels25, 26 to both opposed surfaces 12 and 13. In further contradistinctionto the prior art of FIGS. 1a (i)-1 d(ii), no frame or casing is requiredto hold the panel together.

FIG. 3 is a perspective view of the start of a process line formanufacturing the panel of FIGS. 1a (i)-1 d(ii);

FIG. 4 is a perspective view of part of the process line;

FIG. 5 is a perspective view of a kitchen cabinet incorporatingillumination panels of FIGS. 2a and 2 b;

FIG. 6 is a perspective view of an illumination panel of FIGS. 2a and 2battached to a structural panel;

FIG. 7 is a perspective view of the interior of a refrigerator linedwith panels of the kind illustrated in FIGS. 2a and 2 b;

FIG. 8 is a perspective view of a retail display cabinet usingilluminated walls, back panel and shelving incorporating panels shown inFIGS. 2a and 2 b;

FIG. 9 is a perspective view of a street sign incorporating a panel ofFIGS. 2a and 2b ; and

FIG. 10 is a perspective view of a solar powered panel for use with alight diffusing panel of FIGS. 2a and 2 b.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An illumination panel essentially comprises a transparent sheet of clearacrylic plastics with at least one surface covered with a matrix ofspaced light refracting and reflecting dots. When light is introduced tothe appropriate edges of the panel it is refracted and reflected by thedots and released to illuminate the whole surface of the panel. PatentApplication No. WO 92/05535 is an example of this kind of illuminationpanel. However, it has not hitherto been known to use the dots to adhereadjacent elements of the panel to make them integral.

In the following paragraphs an embodiment of the present invention asdepicted in FIGS. 2a and 2b will be described and explained bycontrasting with typical illumination panels of the prior art,specifically, US 2008/0037272 by Song et al (FIGS. 1a (i) and 1 a(ii)),US 2003/0231483 by Higashiyama (FIGS. 1b (i) and 1 b(ii)), U.S. Pat. No.6,918,679 by Wu (FIGS. 1c (i) and 1 c(ii)) and JP 100 21720 (FIGS. 1d(i) and 1 d(ii)).

FIGS. 2a and 2b show an illumination panel 10 in accordance with theembodiments of the present invention in exploded plan view (FIG. 2a )and in cross section (FIG. 2b ).

Each illumination panel 10 comprises a core 11 of transparent acrylicacting as a light guide panel which is usually 6 mm, 8 mm or 10 mm inthickness. The core may include an optical brightener. The core 11 canhave any surface sectional area and, although shown planar in FIGS. 2aand 2b , could be appropriately curved. The acrylic core 11 has opposedsurfaces 12 and 13, each of which is covered by a matrix of opaque,translucent or clear glue dots 20. The matrix of glue dots 20 is anadhesive to secure a protective panel 25, 26 to both sides of the core11. The protective panel may, for example be a diffuser sheet and/orreflector sheet.

If required, a layer 30, 31 can optionally be added to the outer side ofthe protective panels 25, 26. It is understood that the layer 30, 31 maybe any material such as glass, timber, metal, paint, ink, photographicfilm or veneer which could be attached to the protective panel 25, 26for various purposes, for example painting or veneering a surface tomatch the surroundings, or printing signs and images. The surfaces ofthe protective panels 25, 26 may also be left untreated, simply allowingthe light to release for general illumination.

The important feature of this embodiment is that the matrix of adhesivedots 20 acts as a light transmitting, refracting and reflecting mediumas well as an adhesive, firmly securing the protective panel 25 to thecore 11 and protecting the core and dot matrix from damage, for example,by scratching or moisture while also providing a light transmittingsurface that can be used without affecting light distribution from thecore. The glue is of a light reflecting, refracting or transmittingmaterial and it is understood that there are a large variety ofdifferent glues which are suitable.

The matrix of adhesive dots may be applied in many different waysincluding by etching, painting, printing, screen printing or spraying ortransferred from a film or even as part of a film or layer that is thenfixed to the core by the adhesive dots.

Alternatively, the matrix of dots may be provided by localized spotapplications of energy, such as laser energy from a laser, or highfrequency ultrasonic acoustic vibration from a sonotrode.

For example, a laser can be used to etch the surface of the core 11through the protective panel 25 to define the array of dots whilst, atthe same time, bonding the protective panel to the core. Laser etchingby focusing a laser beam on the surface of a material is a method thatis well known to those skilled in the art for marking a surface. Whenthe laser energy and the speed of laser movement across a targetmaterial is correctly adjusted for the type and thickness of thematerial, the surface of the material at the focal point of the laserbeam will be changed or ‘etched’.

Where used herein the term ‘laser etching’ is intended to mean theapplication of sufficient laser energy to etch the surface of the core,that is, melt and mark to create a matrix of light diffusing dots and atthe same time bond a protective panel or film to the core.

The laser energy is adjusted by controlling the overall energy deliveredfrom the laser (0-100%) and the speed at which the beam is passed overthe material. Typically, for example, when using an 80 micron laminatingpolyester film, a 400 watt laser is adjusted to 8% power, and moving at1 meter per second can effectively etch and bond the film to the core.

Alternatively the matrix of dots may be provided by providing highfrequency ultrasonic acoustic vibrations to create dots whileultrasonically welding the surface of the core to the protective panel.

The process might also be achieved by laying an appropriate film betweenthe core and protective panel and under laser activation, have the filmbond to both surfaces in an array of light transmitting dots.

The invention of the present application can be contrasted with theinventions of US 2008/0037272 by Song et al (FIGS. 1a (i) and 1 a(ii)),US 2003/0231483 by Higashiyama (FIGS. 1b (i) and 1 b(ii)), U.S. Pat. No.6,918,679 by Wu (FIGS. 1c (i) and 1 c(ii)) and JP 10021720 (FIGS. 1d (i)and 1 d(ii)). The prior art examples are shown in exploded plan view(FIGS. 1a (i), 1 b(i), 1 c(i) and 1 d(i)) and in corresponding assembledcross sectional view (FIGS. 1a (ii), 1 b(ii), 1 c(ii) and 1 d(ii)).

As illustrated in FIGS. 1a (i) and 1 a(ii), the invention of Song et alincludes liquid crystal display elements (LCDs) 125, diffuser 120, Lightcollecting layer 130, light emission surface 112, light guide plate 131,Light reflection surface 113, a reflector plate 114 to fully reflectlight released from the light guide plate 131.

In use, all the elements of the panel of Song et al are held together inthe upper 110 and lower casing 160, that is, within a frame. If theframe were to be removed, only the diffuser 120, light collecting layer130 and light guide plate 131 would remain and the panel would notfunction because light would be lost through the light reflectionsurface 113 which would also be exposed and thus vulnerable to damage.

The panel of Song et al (FIGS. 1a (i) and 1 a(ii)) is intended forgathering and guiding light from an edge lit panel onto an LCD screen.The invention is directed to removing the need for providing a pluralityof optical sheets between the light guiding plate and the liquid crystaldisplay to diffuse and focus light. The device of Song et al is made bycontacting a base film printed with a clear, wet UV activated resinagainst a light guide plate in such a manner as to ensure that there ismore surface contact of the resin to the base film than to the lightguide plate. Song et al does not include a matrix of light releasingdots nor a matrix of dots used as an adhesive for bonding two surfacestogether. Furthermore, the device of Song et at is one-sided and is heldto the loose reflector plate by a frame.

Thus Song et al constructs an optical plate from a light guide plate, abase film and a light collecting layer. The light collecting layer isnot a light reflecting and refracting layer. This action is carried outby the reflection surface 113 of the light guide plate. Various patternsmay be formed on reflection surface 113 including a dot pattern, a V-cutgroove, a prism pattern or the like. The light collecting layer is madeusing clear resin, and the resin is laid down on the base film at anincreasing density away from the light source in the light guide plate.So also are the dot pattern, V-cut groove pattern, prism pattern or thelike that are reflecting the light in the light guide plate. That is,the further away from the light source, the denser the light reflectingelements on the rear surface of the light guide 131. Therefore, morelight collecting patterns are required to collect the light on the lightemission surface 112. However, any dots are not an adhesive for bondingto the reflector.

In another example of the prior art, the panel of Higashiyama isdepicted in FIGS. 1b (i) and 1 b(ii). The panel per se comprises a mainLCD screen 279, a prism sheet 216 a diffusion layer 214 to diffuse andreflect light, a light guide plate 212 having a diffusion surface 213, awhite semi-transparent reflective layer 215 and a second LCD 217. Thepanel is intended for use in a small device such as a mobile phone andthe components of the panel are held together by a frame in the form ofthe phone case—the top 211 and bottom 216 of which can be seen in FIGS.1b (i) and 1 b(ii). If the case were to be removed, only the light guideplate 212 with diffusion surface 213 would remain leaving the panelunable to diffuse light, with the diffusion and light releasing surfacesexposed and vulnerable to damage.

Higashiyama (FIGS. 1b (i) and 1 b(ii)) discloses an illumination panelthat uses a light guide plate with a single-sided diffusion surface, anembossed surface of fine projections and transparent resin filmsdisposed on either side thereof. The resin films are for diffusing andreflecting light so more light will be released from a front surface ofa light source device than from a rear surface thereof.

The panel of Higashiyama has an air layer interposed between thediffusion layer 214 and a front facing surface of the light guide plate212 and the embossed surface 213 and the semi-transparent reflector 215.The panel is designed to selectively deliver more light to the frontfacing surface so that the main LCD screen of the phone receives themost light, while a secondary smaller screen on the rear surface of thephone can be illuminated by a lower transmission of light from the lightguide plate 212. There is no teaching or use of adhesive dots in theHigashiyama panel.

In another example of the prior art, the panel of Wu is depicted inFIGS. 1c (i) and 1 b(ii). The panel comprises a light guide panel 321having light deflection parts 322 on its upper and lower surfaces.Reflector or diffuser sheets 323 and transparent plates 324 are also inplace on either surface of the light guide panel 321, the panel beingheld together by screws 312 and brackets 411.

Unlike the panel of the present invention, the prior art panel of Wuuses mechanical means (screws and brackets) to hold components adjacentor in contact with the core. If the screws were to be removed, only thelight guide panel 321 and light deflection parts 322 would remainattached to the core, but light would not be diffused and the lightdeflection parts and both surfaces of the wave guide would be exposedand vulnerable to damage.

In another example of the prior art, the panel of JP 100 21720 isdepicted in FIGS. 1d (i) and 1 d(ii). This panel is used in a lap top orportable computer and includes a diffuser sheet 403, a light guide panel401, adhesive light deflection parts 406 and a reflector sheet 402. Inthe absence of any mechanical fixing or case 407, only the light guide401, reflector sheet 402 and adhesive light deflection parts 406 wouldremain attached to the core and light would not be diffused and thelight releasing side of the light guide panel would be exposed making itvulnerable to damage.

Specifically, prior art edge illuminated light guide panels haveprincipally been used for illuminating signs and LCD display panels forcalculators, cameras, portable computers, television sets and mobilephones. Much refinement of edge light panels has taken place over thelast 15 years, particularly relating to LCD television sets and portablecomputers.

There are three basic elements that commonly make up a single sided edgelight panel systems of the prior art for the abovementioned devices—awave guide panel that distributes and releases light, a reflector tosend light released from the panel in one direction, and a diffuser toprovide a “usable” spread of diffused light.

The wave guide is the key component and operates by releasing lightevenly across either one or both planer surfaces. This is normallyachieved by applying a matrix of dots or laser etched lines thatincrease in area or number in a direction away from the light source,and when done correctly, light is released evenly.

Waveguides are typically made from acrylic. For example the acrylic usedtypically has a refractive index of approximately 1.45 which is higherthan air, so light introduced into the edge of a clear, untouchedacrylic panel will pass through the panel and out the other side, as thelight is internally reflected at the acrylic-air interface. Any marks,scratches, moisture or finger prints change the reflective andrefractive nature of the wave guide surface and this results in lightbeing released, so both surfaces of the wave guide need to be protectedfrom any contact or surface contamination once the correct lightdistribution has been established.

The surfaces of the wave guides used within the above devices remainprotected because they are sandwiched between the reflector and diffuserand all the elements are held together in a frame or case to allow thesystem to work.

While the various wave guides will function outside the cases or framesthey are held within, that is, will act to distribute light from theirsurfaces, the panels are vulnerable to any contact on either surface andtherefore are very limited in application. In essence, embodiments ofthe present invention stem from the realisation that it is possible toremove the frame while providing permanent protection of both the waveguide surfaces by bonding the diffuser and reflector to the wave guideby the matrix of light releasing and reflecting adhesive dots. Thisreleases the edge light panel elements from the need for a frame andallows the panel to be used for a multitude of applications. Because theelements are bonded together, the panel becomes structural as well asilluminating, and this is a very practical and highly innovativedevelopment.

One embodiment of the method of producing the illumination panel of thepresent invention, comprises the step of placing a protective panel inabutting parallel contact with each surface of a transparent structuralcore and laser etching or activating a matrix of light releasing dotsthrough the protective panel onto the surface of the core to adhere thelayer to the core and providing light distribution across thetransparent structural core.

Another embodiment of the method of producing the panel shown in FIGS.2a and 2b is illustrated in FIGS. 3 and 4. In this embodiment, the coreof acrylic plastic 11 is passed along a roller conveyor 100 in thedirection of the arrows shown in FIGS. 3 and 4.

An adhesive dispenser 101 is arranged to complete a reciprocal movementalong a rod 102 transversely across the conveyor 100. The rod 102 isheld by fixed rectangular supports 103, 104. The dispenser 101 places aline of spaced dots of adhesive transversely across one surface of thecore, the adhesive preferably containing a small percentage of pigment,typically from 0.5 to 2.0 wt %, depending on the size of the finishedpanels and the material used for the protective panels. As the coremoves forward, the rows of dots are spaced as shown in FIG. 3. The dotsof adhesive could also be printed for example, by a glass screen printersuch as those sold under the trade mark Keywell™.

Typically the adhesive comprises acrylates. Typically the pigment is awhite pigment, such as a titanium dioxide based pigment. Prior toprinting, a special hardening formulation is added at 3-5% of adhesivevolume and this material assists in cross-linking the adhesive bond tothe material used for the protective panel.

Downstream of the dispenser 101 is a UV light 105 which fully orpartially cures the adhesive depending on type or process. Acommercially available UV curing machine such as those sold under theADCO trade mark may be suitable. The UV energy source is typicallyadjusted to deliver from 600 to 900 milijoules/cm2 depending on thelevel of pigment mixed in the adhesive.

A protective panel 25 is positioned above the first glued surface of thewave guide core in a squaring frame and aligned with the core. The coreand protective panel are then pressed together and consolidated bypassing through a pressing roller 110 that rotates to exert downwardpressure on the panel 25 to bring the cover panel 25 into abuttingcontact with the dots on the core 11 or the panel can be manuallypressed to the dots on the core. The adhered elements are then sent backto have the adhesive applied to the second surface of the wave guidecore. The adhesive is again cured under UV light as described above andthe panel again placed in the squaring frame where the second protectivepanel is aligned and pressed into position as described above.

The three elements making up the finished panel are then pressed under avacuum press at −0.8 to 0.9 Atm, preferably about 0.85 Atm(approximately 8 ton/m2) for 2 to 5 minutes, preferably about 3 minutes.

A significant amount of pressure may be applied, for example, around30,000 kg on a 2500 mm×1300 mm panel according to the present invention.

It is understood that this process may also be achieved by the adhesivebeing applied to the protective panels which are then bonded to thecores.

In another method, the adhesive may be printed to the core or protectivepanel and the two components then pressed together and the adhesivecured by light.

It may also be necessary to alter the surface characteristics of theprotective panels prior to bonding in order to have the adhesive and theprotective panels to bond firmly. For example, if the protective panelsare made from acrylic, polycarbonate or other plastic material, they maybe passed through corona discharge plasma to raise the surface energy topreferably between 50 and 55 Dyne/cm2. It may also be helpful to treatthe acrylic core in the same way.

The dot matrix substantially covers the surface of the core 11 andoperates to control the release of light introduced along one or moresides of the panel 10. It is usual for the density or size of dots, orboth to increase along the panel 10 in a direction away from the edgewhere the light is introduced for a single light source, and when lightis introduced from opposite sides of the core panel, the density or sizeof dots or both increases to a point equal distance from both lightsources. To achieve an even light distribution across the core panel,the density of dots can be increased or alternatively, the gaps betweenthe dots can remain constant and the size of the dots increased, or boththe density and size of the dots increased.

The dots may comprise a grid work of lines or even concentric circles ofdiffering diameters. The adhesive dots may be any one of a number ofadhesive materials including various formulations of UV curing inks andadhesives, and adhesive of clear or white silicon.

Both panels 10 described above are in themselves structural units andthus can be supported or used as wall panels, shelves or in a widevariety of structural environments. The panels do not have to beenclosed within a supporting frame and can, by themselves, operate asstructural elements.

In one embodiment, it is envisaged that at least one edge of the panelwould have LEDs embedded therein which would operate on low voltage todefine a highly illuminated structural element. The panel may also befinished with a dress edge on one or more sides. The LEDs could also besimply attached to one or more edges of the panel by a metal or plasticextrusion, or clips. The dress edge may be made from translucent acrylicto allow light to be released. The advantage of embedding LED lightinginto the panel means that, as a structural unit, it is complete. SinceLEDs have a long lifespan the panels could be left illuminated for verylengthy periods operating on a low safe voltage without the need ofmaintenance. The light delivered could be white or any number ofdifferent colours available from LED lighting elements.

In another embodiment, the protective panel 25 could be either a lighttransmitting diffuser panel or a reflective reflector panel. Theprotective panel could be a suitable material such as plastic, glass,metal or timber such as the acrylic and polyester surfacing providedunder the Laminex® trade mark. The surface of the panel 25 that is to bebonded to the core could be painted or treated to define a reflectivesurface when the panel operates as a reflector.

For example, a white polystyrene or polyethylene panel may be bondeddirectly to the core 11 with the surface of the plastic reflecting thelight released from the core by the glue dots. The opposite side of thecore could be bonded to a glass sheet. This arrangement could be usedfor a kitchen splashback or a glass shelf.

Alternatively, the opposite side of the core could have an opaltranslucent panel bonded by the matrix of adhesive dots, and used as asingle sided sign.

In a further example, a decorative surfacing such as those sold underthe trade mark Laminex® may be bonded directly to the core 11 with theinside (or bonding) surface of the veneer having been painted white toreflect light. The veneer then provides the finished external surfacewhile the internal face of the veneer acts to reflect light back throughthe core and out the opposite surface. This front light releasingsurface of the core can be protected by a clear or opal translucentmaterial that is attached by another light releasing matrix of gluedots. This could be the case when the illumination panel is used as thewalls and/or base of a cupboard, or a retail display, see FIGS. 5 and 8.

A rectangular kitchen cupboard 50 is shown in FIGS. 5 and 6, comprisinghinged doors 51, 52, a top 53, sides 54, 55, base 56 and rear panel 57.The rear panel 57, top 53 and doors 51, 52 are manufactured ofconventional joinery such as plastic or polymer, plywood, timber, chipboard or combinations thereof. The base 56 and sides panels 54, 55 areconstructed of illuminated panels 10 shown in greater detail in FIG. 6.

In FIG. 5, the cupboard is mounted against a wall 60 above a benchsurface 61. Since the side panels and base panels are illuminatedpanels, light is passed into the interior of the cupboard by the sidepanels and down onto the bench surface 61 by the base panel 56.

As shown in FIG. 6, each panel 10 comprises an acrylic core 11 with amatrix of dots 20 on either side. The matrix of glue dots secures areflective cover 25 on one side and a translucent layer 26 on the otherside. The edge of the panel has attached thereto an elongated lightstrip 65 and the light strip, together with the panel, is located withina rectangular aluminium extrusion 70. The extrusion 70 has an upstandingweb 77 which is keyed into a slot 72 in the panel 57 which constitutesthe timber, veneer or laminated structural rear panel 57 of the cabinet.

The side panels may transmit light either internally into the cabinet oron both sides and the base panel is designed primarily to transmit lightto the underside. A single or dual light source is located along therear and or front edges and a reflective covering is placed on the topside. Where the light travels in both directions it is understood thattranslucent panels would be used on both sides.

In FIG. 7, there is an illustration of an embodiment where illuminatedpanels 10 are incorporated as the walls of a refrigerator 40. The panelshave at least one edge lined with LEDs. The core 11 is bonded to areflecting panel or the wall of the refrigerator so that each side wall41, 42 and rear panel 43 constitutes a light source. A translucentacrylic panel is bonded to the core to provide the hard wearing exteriorsurface within the interior of the refrigerator. A door operated switch(not shown) can be used to control operation of the lights. In bothembodiments shown in FIGS. 5 to 7, it is understood that the shelvescould incorporate illumination panels of the kind described above.

In FIG. 8, there is an illustration of a retail display 65 in which theside walls 66, 67, back panel 68 or shelving 69 could be manufactured ofilluminating panels 10 of the kind described above. As described inearlier embodiments, a line of LEDs is secured along the edges of theside walls and rear wall and along one or more edges of the shelves andthe core is covered on both sides by acrylic or glass panels to providehard wearing surfaces that can be used as shelving in retail displays,or carry images and branding information.

In FIG. 9, there is an illustration of a street sign 80 comprising anelongate rectangular panel 10 incorporating a core 11 and front and reartranslucent acrylic faces 25, 26. The longitudinal and side edges of thepanel are sealed and LED elements 81 are positioned along the inneredge. The whole assembly is attached to an aluminium extrusion 82 whichforms a housing that allows the panel to attach to a post and which inturn contains a battery or transformer to power it as an illuminatedstreet sign. The printing can be carried on either acrylic face.

In the embodiment shown in FIG. 10, a solar panel 90 incorporates anilluminated panel 10 of the kind described above whereby solar panels inthe form of photo voltaic cells with a reflective under surface arebonded directly to the core, or to the exterior of the panel 10 on thetop surface and they are coupled to either battery storage or batterypacks which in turn power LEDs 92 positioned down the side edges of thepanel. The edges of the panel can be protected with an acrylic or metaledging strip 94, 95 and, in this manner, the panel absorbs the solarenergy during the day which can be stored as electricity in a batterypack ensuring that the panel is illuminated at night.

In this panel, a translucent diffuser is bonded to the core 11 to definethe underside of the panel and the upper side of the panel has areflective surface that is part of or which supports the solar panels91.

In another embodiment, the core could comprise a series of thin panelseach with appropriate positioning of adhesive dots which are inalignment or offset from the adhesive dots on the adjacent panel. Inthis way a laminated structure is produced with an added dimension ofdot matrix refinement; in the direction horizontally away from the lightsource the dots may get bigger on each layer and then vertically in thedirection of the light being released the dots may get proportionallysmaller. Seen from the light releasing face, the dots may appear tocover the surface, but in fact they may be positioned on each layer indifferent positions.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to expresslanguage or necessary implication, the word “comprise” or variationssuch as “comprises” or “comprising” is used in an inclusive sense, thatis, to specify the presence of the stated features but not to precludethe presence or addition of further features in various embodiments ofthe invention.

Having described the invention, the following is claimed:
 1. Anillumination panel comprising a transparent structural core having twoopposing surfaces, a matrix of light releasing dots substantiallycovering both said opposing surfaces, and a protective panel in abuttingcontact with each of said opposing surfaces whereby the matrix of dotsincludes a pigment of between 0.5 to 2.0 wt % and is configured as alight transmitting, refracting and reflecting medium as well as anadhesive for bonding the core to the protective panels so that theillumination panel operates as a structural element without a supportingedge frame, and wherein the density or size of the dots increases acrossthe illumination panel in a direction away from an illumination paneledge adjacent a light emitting element.
 2. The illumination panelaccording to claim 1, wherein a transparent or translucent protectivepanel is bonded to both sides of the core.
 3. The illumination panelaccording to claim 1 wherein an outer layer is bonded to the protectivepanel.
 4. The illumination panel according to claim 3, wherein the outerlayer is paint, ink, a transfer, metal, glass, plastics, wood or woodveneer.
 5. The illumination panel according to claim 1, wherein the coreis acrylic.
 6. The illumination panel according to claim 1, wherein thelight releasing dots comprise a pressure sensitive adhesive.
 7. Theillumination panel according to claim 1, wherein the protective panel ismetal, timber, plastics or glass and can be translucent or reflective.8. The illumination panel according to claim 1, wherein the matrix ofdots is applied to the transparent core by etching, painting, screenprinting, printing or spraying, or transferred from or as part of afilm.
 9. The illumination panel according to claim 1, wherein the matrixof dots is provided by ultrasonically welding the surface of the core tothe protective panel.
 10. The illumination panel according to claim 1,wherein the matrix of dots is provided by induction, dielectric ormicrowave activation of a distributed receptor that bonds the surface ofthe core to the protective panel.
 11. A method of manufacturing theillumination panel according to claim 1, including the step of curingthe matrix of dots by UV light or infra-red heating or laser activationto bond the surface of the core to the protective panel.
 12. Theillumination panel according to claim 1, wherein a reflective protectivepanel is bonded to one side of the core with a transparent ortranslucent protective panel being bonded to the other side.
 13. Theillumination panel according to claim 1, wherein a light is positionedadjacent or on one or more edges of the panel.
 14. The illuminationpanel according to claim 13, wherein the light releasing dots increasealong the panel in density, size or combinations thereof across thepanel in a direction away from the light source.
 15. The illuminationpanel according to claim 13 wherein the lights comprise a plurality ofLEDs secured to or embedded in one or more edges of the panel.
 16. Acabinet having walls and shelves, some of the walls or shelvescomprising illumination panels according to claim 1 with a light sourceadjacent or in one or more edges of each panel.
 17. A shelf comprisingan illumination panel according to claim 1 with a light source adjacentor in one or more edges of the panel.
 18. A sign comprising anillumination panel according to claim 1 attached to a housing having amounting flange adapted to be secured to one edge of the illuminationpanel and a light positioned adjacent or on one or more edges of thepanel wherein the light is wired to the interior of the housing.
 19. Amethod of producing an illumination panel according to claim 1, themethod comprising the steps of: placing a protective panel in abuttingparallel contact with a transparent structural core and establishing amatrix of light releasing dots by applying energy through the protectivepanel onto the surface of the core to adhere the protective panel to thecore and provide light distribution across the transparent structuralcore.
 20. A method of producing an illumination panel according to claim19 wherein the energy applied is chosen from laser energy, ultrasonicenergy, IR energy, and microwave or electron beam energy.
 21. A methodof producing an illumination panel according to claim 19 which includesthe further step of raising the surface energy of a surface of thetransparent structural core prior to placing a protective panel inabutting parallel contact with said surf ace surface.
 22. A method ofproducing an illumination panel according to claim 19 which includes thefurther step of raising the surface energy of surface of the protectivepanel prior to placing the protective panel in abutting parallel contactwith the transparent structural core.
 23. A method of producing anillumination panel according to claim 19 further including the step of:dispensing adhesive to form the matrix of light releasing dots on thesurface of the core, and subsequently applying UV energy to activate thematrix of light releasing dots.
 24. The illumination panel according toclaim 1 wherein solar film or solar cells are bonded to a surface of theprotective panel.
 25. The illumination panel according to claim 1,wherein the pigment comprises a titanium dioxide based pigment.
 26. Theillumination panel according to claim 1, wherein the pigment comprises awhite pigment.